The objective of the proposed research is to identify the viral genes involved in herpes simplex virus-induced transformation and to elucidate their role in the transformation process. For this purpose, the HSV genome will be cleaved using restriction endonucleases and transformation will be attempted with specific HSV DNA fragments. Should a fragment be shown to induce transformation, the identify of the viral genes encoded by the fragment will be determined using ts mutants in marker rescue experiments. Additional genes encoded by the fragment will be identified by mutagenesis of the fragment itself and by rescuing induced ts mutations through coinfection with the wild-type virus. Whether each gene encoded by the transforming fragment is essential for transformation or not will be determined by attempting to induce temperature-sensitive transformation using HSV-DNA fragments bearing ts mutations in each gene. The specific functions of viral genes encoded in the transforming fragment will be elucidated by phenotypic characterization at permissive and non-permissive temperatures of a) the corresponding ts mutants, and b) the temperature-sensitive cells transformed by the DNAs of these mutants. Marker rescue and complementation tests using HSV ts mutants in a variety of HSV transformed cells will demonstrate whether the genetic information present and functioning in these cells is qualitatively the same or different.